Copper base alloy



United States Patent Ofice 3,522,039 COPPER BASE ALLOY Charles D. McLain, Alton, Ill., assignor to Olin Mathieson Chemical Corporation, a corporation of Virginia No Drawing. Filed June 26, 1967, Ser. No. 648,996 Int. Cl. C22c 9/00, 9/04 U.S. Cl. 75157.5 9 Claims ABSTRACT OF THE DISCLOSURE The present disclosure teaches an improved copper base alloy containing from 1.5 to 3.5% iron and small amounts of zinc or mixtures of zinc and phosphorus. The alloys in the present specification are characterized by improved physical properties, in particular high strength and high conductivity.

As is well known in the art, copper is an excellent conductor of electricity. Numerous alloying additions have been proposed in order to increase the strength of copper. 'In so doing, the electrical conductivity of the copper is markedly reduced.

It is, therefore, highly desirable to provide a copper base alloy characterized by high conductivity and increased strength.

Accordingly, it is a principal object of the present invention to provide a copper base alloy characterized by high electrical conductivity and high strength properties.

It isa further object of the present invention to provide a copper base alloy with annealed physical properties which do not have a wide variation.

It is a further object of the present invention to provide a copper base alloy having the ability to attain various strength levels as a result of different annealing treatments, even when small amounts of impurities are present.

It is a further object of the present invention to provide an improved copper base alloy having a combination of high strength, high conductivity, and other excellent physical properties.

It is an additional object of the present invention to provide a copper base alloy which is inexpensive and wherein the excellent physical properties are easily obtainable.

Further objects and advantages of the present invention will appear from the ensuing specification.

In accordance with the present invention it has been found that an improved copper base alloy is provided which effectively achieves the foregoing objects and advantages. The alloy of the present invention comprises a copper base alloy consisting essentially of from 1.5 to 3.5% iron, from 0.01 to 0.15% phosphorus, from 0.03 to 0.20% zinc and the balance essentially copper. Throughout the ensuing specification all percentages are percentages by weight.

In accordance with the present invention, it has been surprisingly found that the foregoing alloys are characterized by numerous unexpected and surprising advantages. For example, the alloys of the present invention have an unexpected improvement in electrical conductivity. Namely, there is readily obtained an IACS electrical conductivity in excess of 70% IACS. Furthermore, the alloys of the present invention have excellent annealing characteristics, with the ability to attain various strength levels as a result of different annealing treatments. In addition, the alloys of the present invention attain high 3,522,039 Patented July 28, 1970 rolled temper strength levels. Still further the high electrical conductivity of the alloys of the present invention is coupled with excellent annealed tensile strength properties of approximately 55 ,000 psi and higher. The strength and physical properties of the alloys of the present invention are not significantly variable if small amounts of impurities are present. In addition to the foregoing, the alloys of the present invention are inexpensive and their excellent physical properties are easily obtainable.

The composition of the alloys of the present invention is as stated heretofore. The preferred iron content is from 1.8 to 2.9%, the preferred phosphorus content is from 0.03 to 0.10% and the preferred zinc content is from 0.05 to 0.2 and optimally from 0.1 to 0.2%.

In view of the high and in fact surprising physical properties of the alloys of the present invention, the percentage ranges of the alloying ingredients are important.

In addition to the foregoing, small amounts of additional alloying ingredients may be, of course, included in order to achieve particularly dseirable results, for example, aluminum in an amount up to 0.07% and manganese in an amount up to 0.08%. Also, small amounts of impurities may, of course, be tolerated.

The alloys of the present invention attain improvement over conventional alloys in a wide range of processing. Naturally, however, particular processing will result in variation in properties.

The manner of casting the material is not particularly critical, with conventional casting methods for these types of alloys being readily utilizable, it being noted that higher temperatures should be used in order to solutionize the iron. It is preferred to cast the alloy into billets of con ventional size, subjecting them to hot working, as by rolling in the conventional size.

After casting the alloy should be hot rolled at an elevated temperature, i.e., from 800 to 1050 C., with a temperature of about 950 C. being preferred. The alloy should then be cold rolled to gage, with intermediate anneals, with cold reduction in excess of 50% between anneals being preferred. Annealing temperatures of from 400 to 600 C. are preferred, with annealing time at temperature preferably being a minimum of two (2) hours. Longer times'may be utilized, if desired, for improved electrical conductivity. Continuous strand annealing of strip or mill products will achieve the same high level of physical properties as with Bell annealing, but will not achieve as high a level of electrical conductivity. Therefore, for development of both high annealed strength and electrical conductivity, final annealing and preferably in processing annealing must be in batches with conventional furnace cooling, such as Bell annealing.

Detail processing and preferred processing parameters consonant with the foregoing are found in co-pending application Ser. No. 648,742 for Process for Treating Copper Base Alloy, filed of even date herewith, by C. D. McLain.

The present invention will be more readily understandable from a consideration of the following illustrative examples.

EXAMPLE I Alloys were prepared in the following manner. High purity copper and high purity iron were melted together in a low frequency, slot type induction furnace under a charcoal cover at approximately 1200" C. About 10% of the copper charge was held back and the melt was slightly overheated to about 1300 C. in order to put the iron into solution. High plurality alloying additions were added when the molten mass was at about 1300 C. The balance of the copper was added and the melt brought 4 five inch thick slabs were hot rolled at 925 C. to 0.350", milled to 0.300", cold rolled to 0.100, annealed for two hours at 490 C., cold rolled to 0.050", annealed at 490 C. for two hours, and cold rolled to 0.025 and annealed for two hours at 440 C.

to the pouring temperature of about 1200 C. The melt After each anneal the tensile strength and electrical was then poured into a water-cooled ingot mold of 28% conductivity of each sample was determined and the re- 5" X 96" at a pouring rate of 21.3 per minute. sults are shown in the following table.

TABLE IV First anneal A Second Anneal Third Anneal Tensile Electrical Tensile Electrical Tensile Electrical Strength, Conductivity, Strength, Conductivity, Strength, Conductivity Alloy p.s.i. percent IACS p.s.i. percent IACS p.s.i. percent IACS The alloys thus prepared had the following composition.

EXAMPLE II Alloys 1 and 2 prepared in Example I were processed as follows. The alloys were hot rolled at from 900 to 940 C., followed by a water spray quench to room temperature. The materials were then cold rolled to 0.100, Bell annealed at 480-600 C. (1 to 4 hours at temperature), cold rolled to 0.050", Bell annealed at 460 to 480 C. (1 to 3 hours at temperature), and cold rolled to 0.025 gage and Bell annealed at 440 to 480 C. (1 to 3 hours at temperature).

The alloys were then tested for physical properties, with the results being shown in the following table.

The foregoing demonstrates that alloy 1, the alloy of the present invention develops greater annealed strength levels than conventional alloy 2 with comparable electrical conductivity.

EXAMPLE III In this example three alloys were prepared in a manner after Example I, wherein the alloys had the following compositions:

TABLE III Phosphorus, Iron, Zinc, Alloy percent percent percent Copper 3 0.045 2.4 0.12 Essentially balance. 4 0.025 2.4 Do.

The alloys were processed in the following manner. The

In an alternative, but less preferred embodiment, one may utilize a copper base alloy consisting essentially of from 1.5 to 3.5% iron, from 0.03 to 0.28% zinc, preferably from 0.05 to 0.25% zinc, and the balance essentially copper.

This invention may be embodied in other forms or carried out in other ways without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered as in all respects illustrative and not restrictive, the scope of the invention being indicated by the appended claims, and all changes which come within the meaning and range of equivalency are intended to be embraced therein.

What is claimed is:

1. A copper base alloy consisting essentially of from 1.5 to 3.5% iron, from 0.01 to 0.15% phosphorus, from 0.03 to 0.20% zinc and the balance copper.

2. A copper base alloy according to claim 1 containing from 1.8 to 2.9% iron.

3. A copper base alloy according to claim 1 containing from 0.03 to 0.10% phosphorus.

4. A copper base alloy according to claim 1 containfrom 0.1 to 0.2% zinc.

5. A copper base alloy according to claim 2 ing from 0.05 to 0.2% zinc.

6. A copper base alloy according to claim 2 containing from 0.03 to 0.10% phosphorus.

7. A copper base alloy according to claim 6 containing from 0.1 to 0.2% zinc.

8. A copper base alloy consisting essentially of from 1.5 to 3.5% iron, from 0.03 to 0.28% zinc and the balance copper.

9. An alloy according to claim 8 containing from 0.05 to 0.25% zinc.

contain- References Cited UNITED STATES PATENTS 2,155,406 4/1939 Crampton -157.5

CHARLES N. LOVELL, Primary Examiner US. Cl. X.R. 75153; l48-32.5 

